Increasing use of hazardous chemicals to make various plastics, pesticides, and numerous other household and industrial products in use today has led to increased risk of contamination of large areas for extended periods due to accidents during transport or manufacturing processes using such chemicals. Industrial environments also require continuous protection for workers in some areas due to risks of exposure to chemical or biological agents in their day-to-day work environment. Unfortunately, there is also an increased risk in modern society for contamination of large areas for extended periods by persistent biological or chemical warfare agents (or other hazardous materials) spread intentionally by terrorists or other individuals or groups.
Risks from accidental spills, terrorist acts, or other potential exposures to biological agents and hazardous chemicals have led to creation of hazardous materials (HAZMAT) response teams equipped with protective suits and protected or self-contained breathing air supplies. Possible use of chemical and biological weapons in modern warfare has also led to development of chemical and biological protective suits and breathing air filters for military and other defense applications. Different types of protective suits are available for use in different environments involving different types of chemical or biological agents. Such suits may be seen, for example, at Internet website www.approvedgasmasks.com.
In the current art, protected breathing air is generally furnished by either a compressed gas cylinder containing a breathable air mixture, or by powered or unpowered air filter units. In some cases, units capable of releasing breathable oxygen via a chemical oxygen generation reaction are used. Compressed gas cylinders, such as those manufactured and marketed as Scott Air Paks™ by Scott Health and Safety, Monroe, N.C. (www.scotthealthsafety.com), support operations in areas or conditions where oxygen may be depleted, as in burning buildings, or in unknown conditions where there is not high confidence that filtration alone can provide non-toxic breathable air. Air filter units typically employ activated carbon filter cartridges, such as those available in various models from the 3M Corporation, Maplewood, Minn., that are capable of filtering and removing numerous chemical compounds from filtered air by adsorption to surfaces of carbon particles, including some called activated carbon or activated charcoal. Some filter cartridges also employ catalysts or other compounds to help neutralize specific contaminants. Generally, air filter units are also capable of removing particulates from air passing through the filter units, including potentially hazardous dust, powder, or smoke particles and many airborne biological agents, such as anthrax spores, airborne bacteria, and the like. Air filter cartridges may be attached directly to the front or sides of air masks, or an air filter unit may be worn on a belt, back, or chest pack and connected to an air mask via a flexible hose. In unpowered filter units, air is typically pulled through filter units in a cyclic manner by pressure differentials created in a mask or mouthpiece by normal inhalation and exhalation respiration pressures of a wearer. In some cases, one-way intake air valves and one-way exit valves on masks provide for one-way air flow through air filter units and prevent contamination or loading of filter units by moisture and other components in a wearer's exhaled breath. Powered air purifying respirator units employ a powered fan or blower to draw or push air through one or more air filter cartridges or other types of filters into a sealed system, and then provide filtered air from the sealed system to a user via a hose, pipe, or other apparatus connected to a mask, mouthpiece, faceplate, helmet, hood, or other device through which protected breathing air is provided to a wearer. Advantages of powered air purifying respirator units include being able to provide filtered air to a wearer at a nominal pressure slightly above atmospheric pressure, which makes it easier for a wearer to breathe without having to overcome air flow resistance of an air filtering cartridge. Slight positive pressure, with respect to atmospheric pressure, provided by a powered respiratory unit also helps maintain positive pressurization within a mask, faceplate, or hood so that any seal deficiencies or other leaks result in an outflow of clean air instead of an inflow of contaminated air. Powered respiratory units are typically powered by one-time use batteries or by rechargeable batteries. Batteries and filter cartridges typically last approximately eight to twelve hours before they must be replaced or recharged.
In case of an accidental or intentional release of hazardous chemicals or biological agents, a general procedure is for HAZMAT teams to respond to a safe area near the release site, generally upwind of any contaminated area, and then don protective gear in the safe region before entering a contaminated area to rescue or recover victims or take actions to reduce or eliminate the hazard or reduce its effects. Such actions, for example, may involve stopping a leak or cleaning up spilled materials. However, the potential widespread nature of some accidents or intentional releases of hazardous materials may make complete cleanup impractical, requiring resumption of critical activities in a partially contaminated region, and the critical nature of some facilities may make it necessary to continue or resume operation even in an environment that still contains significant contaminants. Typically, after an initial response to a scene of a contamination event, testing and analyses of contaminating chemicals or biological agents are performed to characterize such contaminants and permit tailoring of protective measures to be effective against identified contaminants without additional burdens of maintaining protective measures that are not necessary.
Protective gear in current art is generally designed to provide only relatively short term protection while an individual is in a contaminated area. Protection timelines typically range from an hour or so for individuals using self contained breathing apparatus, such as Scott Air Paks™, or up to eight to twelve hours for individuals using powered breathing apparatus, such as the Breathe Easy™ system made by 3M Corporation. Current technologies for providing protected breathing air supplies do not also provide a capability for decontamination of interior surfaces of a protective suit or vehicle compartments, or for decontamination of contaminated clothes or skin of a wearer.
Increasing possibilities of accidents or terrorist acts creating contamination for extended periods over widespread areas by persistent biological or chemical agents make it desirable to have technologies and methods that can support long term operations in contaminated areas and also provide for decontamination of interiors of protected suits and vehicles used in such contaminated areas. In a widespread accident or attack, it may be difficult to find known clean areas within which to don protective suits and other protective equipment. In an accident or surprise attack, victims' clothing or skin may become contaminated before they can escape or don protective equipment. It is thus desirable to have a capability to sterilize or decontaminate interior surfaces of protective suits, as well as a wearer's clothing and skin, after a protective suit has been donned and while it is being worn by an individual. Similarly, since vehicles, including trucks, cars, aircraft, train cars, and the like, already present near a site where hazardous chemicals or biological agents are released, or responding to such a site, may be needed to provide shelter from inclement weather or a contaminating environment, it is desirable to have a capability to decontaminate passenger compartments or other compartments of vehicles used to respond to, operate within, or provide protection from, contaminated areas, as well as a capability to provide breathable air to victims or rescue and cleanup personnel who may need to use vehicles for shelter and transportation. In some situations, there may also be a need to protect pets, food animals such as cattle, pigs, chickens and the like, and other assets and resources requiring decontamination and breathable air during and after releases of chemical and biological agents. Furthermore, since releases of chemical and biological agents may occur at night, or require operations into the night, or in locations that are not well lighted, and may require operations using battery power or other limited power sources, it would also be desirable to be able to generate light in a visible portion of the electromagnetic spectrum using energy from the decontamination and breathable air supply apparatus that might otherwise be wasted. It is further desirable that such capabilities avoid a need for expensive special purpose equipment such as compressors to refill compressed air cylinders, or a need for a massive supply of filter cartridges which must be replaced after only a few hours of use.
The present invention provides innovative designs and methods for decontaminating interiors of protective suits, vehicles, and other enclosures, as well as clothing, skin, and hair of humans and other animals, and for providing purified breathing air to occupants of protected suits or enclosures, or to other humans or animals using embodiments designed just for breathing air, by employing proven germicidal capabilities of ultraviolet radiation as well as proven air purification and germicidal capabilities of ozone and ozonites produced by use of vacuum ultraviolet radiation and Corona discharge techniques. In some embodiments, ultraviolet radiation is also used to break down ozone to make air sterilized by use of ozone, ozonites, and ultraviolet radiation safe to breathe. Additional innovations in the present invention allow realization of benefits noted above with less power and weight than has been required previously in the ozone air purification art, and at lower costs. Other innovations enhance overall efficiency of emergency operations by also generating light in visible portions of the electromagnetic spectrum using ultraviolet light that would otherwise be wasted and contribute to heat generation in a process of generating or destroying ozone.
Past disclosures by Applicant have described generation of ozone and ozonites by use of ultraviolet mercury vapor lamps. Mercury vapor lamps create, within a plasma of an arc discharge, ultraviolet radiation over a range of wavelengths that includes both 185 nm and 254 nm. Mercury vapor lamps having containment tubes made of purified quartz allow passage, with only moderate attenuation, of ultraviolet radiation with wavelengths as short as 185 nm or somewhat less (also referred to as vacuum ultraviolet, or VUV, radiation). A degree of transmission through quartz of radiation having wavelengths near 185 nm through is generally dependent on purity of the quartz. VUV radiation that includes radiation having wavelengths shorter than approximately 200 nm is capable of breaking molecular bonds within diatomic oxygen molecules, freeing mono-atomic oxygen atoms, some of which then recombine with other diatomic oxygen molecules to create ozone molecules, which contain three oxygen atoms. However, it should be noted that, in some contexts, the term vacuum ultraviolet radiation includes wavelengths significantly shorter that 185 nm, and could include wavelengths shorter than approximately 160 nm that cause undesirable, for air purification applications, breaking of bonds and disassociation of diatomic nitrogen molecules in exposed air. Thus, for purposes of this Application, the term “VUV” radiation is hereby defined to include ultraviolet radiation containing wavelengths near 185 nm capable of breaking bonds of diatomic oxygen molecules and promoting production of ozone, but excluding wavelengths short enough to cause undesirable ionization of nitrogen molecules in exposed air. This is a useful operating definition of VUV radiation for purposes herein since wavelengths sufficiently short to cause disassociation of nitrogen molecules are not transmitted significantly even by purified quartz, which is a material used for containment tubes of ultraviolet lamps intended to permit transmission of 185 nm radiation from a mercury plasma discharge. (Other materials, that may be available or that may become available, that transmit both VUV and UV-C radiation and also tolerate exposure to VUV and UV-C radiation, and to temperatures and pressures associated with containment of mercury vapor plasma discharge, could be used in lieu of quartz in various embodiments of VUV lamps of the instant invention.) Ozone molecules, mono-atomic oxygen atoms, and some other compounds and free radicals including hydroxyl radicals, collectively called ozonites, formed during exposure of air, especially air containing normal to high levels of humidity, to VUV radiation, are highly reactive and are capable of breaking down, via oxidation or advanced oxidation processes (AOP), many hazardous chemicals and biological agents flowing in an air stream exposed to VUV radiation. The energetic nature of VUV radiation can also contribute directly to other reactions or breaking of chemical bonds within chemicals or biological agents exposed to such radiation, thereby providing a germicidal action for biological agents and contributing to breakdown of hazardous chemicals into non-toxic or less hazardous compounds. Beneficial decontaminating oxidation reactions of ozone and ozonites continue within an ozonated air stream after exiting a VUV exposure chamber, and in a volume within which a thus ozonated air stream is allowed to flow, and include reactions with contaminants on surfaces and within porous materials. Ozone and ozonites in an ozonated air stream also react with contaminants in air that did not flow through a VUV radiation chamber but which is mixed with ozonated air.
Since it is undesirable for humans and other animals to breathe air containing a high concentration of ozone, Applicant's invention utilizes mercury vapor plasma tubes that emit a spectral line at 254 nm to destroy ozone molecules. However, it should be noted that other sources of ultraviolet radiation, such as lasers and solid state light emitting diodes, having wavelengths shorter than about 300 nm, may also be used to destroy ozone. As such, for purposes of this application, the term “UV-C” radiation is defined as ultraviolet radiation generally between about 200 nm and 300 nm to cause breaking of bonds within, and disassociation of, ozone molecules. As noted earlier, such radiation within this range is also produced within a discharge region of a mercury vapor lamp. When a tube used as a containment tube for a mercury vapor lamp is made of ordinary silicate glass, or doped quartz containing impurities that prevent transmission of VUV radiation, rather than purified quartz, ultraviolet radiation having wavelengths shorter than 240 nm to 250 nm is attenuated strongly within the glass or doped quartz tube while radiation having wavelengths near 254 nm or greater is passed with much less attenuation. Thus, previous disclosures by Applicant have shown how a mercury vapor discharge lamp made with ordinary glass or doped quartz, referred to as a UV-C lamp, may be used in an apparatus to expose air containing ozone to UV-C radiation to reduce ozone concentrations to levels safe for breathing by humans and other animals. In different applications and embodiments described earlier by Applicant, separate VUV and UV-C lamps are operated simultaneously, or separately at different times, in order to produce different effects and concentrations of ozone and ozonites.
Some embodiments of the instant invention may similarly employ separate VUV and UV-C lamps in novel ways to provide for decontamination of interiors of protective suits, vehicles, and other enclosures. Some embodiments may also provide a source of purified and de-ozonated air for breathing by humans or animals. However, as a further innovation that may reduce weight and power needs, or reduce costs, of some embodiments, Applicant also reveals an innovation whereby both creation and destruction of ozone may be accomplished using a single mercury vapor discharge lamp, and additional innovations for some embodiments that will allow light to be generated as a source of illumination, similar to illumination provided by a flashlight or a miner's head lamp, to support operations at night or in dark areas, using energy that would otherwise be wasted in heat generation. For operations at night or in dark locations, an ability to also generate light in the visible or near-infrared portions of the electromagnetic spectrum will help make maximum use of available power, such as batteries carried by an individual.
It is thus one object of the instant invention to provide apparatus and methods for decontaminating interiors of protective suits and vehicles, clothing and skin of personnel, and other assets of at least some categories of hazardous biological and chemical agents. It is another object of the invention to provide purified air for breathing to support short or long term operations in contaminated areas as well as other applications. It is yet another object of the instant invention to provide apparatus and methods whereby humans or other animals contaminated by exposure to biological or chemical agents may be decontaminated before entering a clean zone for habitation or treatment, and whereby humans or other animals infected with biological agents may be maintained in isolation during a period of contagiousness when they might expose others. It is yet a further object of the invention, in some embodiments, to provide a source of visible light. Other objects of the invention will become clear upon a reading of the following specification.